3 answers

Instead of using traditional "image swap" behaviors with javascript, look into background-image repositioning with CSS. It's really simple and very elegant. This link gives a good summary of the method:

We use this nifty javascript function. You would of course replace ./path/to/your/image/image.png with the path to the image you want to become the bg image to the link. *Edit: Pardon, forgot to add the class function as well.